To convert pascals to centimeters of water, multiply by 0.01019716213. That factor is the whole relationship: both units measure pressure, so the conversion is a proportion with no offset and no substance-specific constant.
The unit ventilator and CPAP pressures are set in. The SI unit: one newton per square metre.
Gauge versus absolute. A tyre gauge reading 32 psi means 32 psi above atmospheric, which is about 46.7 psi absolute. Converting the number is straightforward; remembering which zero it was measured from is where the mistakes happen. N/mm² and MPa are the same size, so a drawing quoting either is quoting the same stress. Below the calculator there is a step table for the values people look up most, and a second table putting real pressure figures into centimeters of water so the number you get has something to be compared against.
The formula
pascals- The amount you are converting, in pascals
0.0101971621298- The exact number of centimeters of water in one pascal
centimeters of water- The converted result
How it works, step by step
- Enter the value in pascals.
- It is multiplied by 0.0101971621298, the exact factor between the two units.
- The answer is shown in centimeters of water, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A car tyre: 2.21e+05 Pa in centimeters of water
A car tyre comes to about 2.21e+05 Pa. Multiplying by the factor: 2.21e+05 × 0.0101972 = 2253.57 cmH₂O. Dividing the answer back by 0.0101972 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A bicycle tyre: 6.21e+05 Pa in centimeters of water
A bicycle tyre comes to about 6.21e+05 Pa. Multiplying by the factor: 6.21e+05 × 0.0101972 = 6332.44 cmH₂O. Dividing the answer back by 0.0101972 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many centimeters of water are in one pascal?
Exactly 0.0101971621298. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert pascals to centimeters of water?
centimeters of water = pascals × 0.0101971621298. Reversed, pascals = centimeters of water ÷ 0.0101971621298, which is the same as multiplying by 98.0665.
Which is the bigger unit, the pascal or the centimeter of water?
The centimeter of water. One pascal is only 0.0101972 of a centimeter of water, so it takes 98.0665 pascals to make one centimeter of water.
What does this quantity actually measure?
Both units measure pressure. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a pascal?
The SI unit: one newton per square metre.
What is a centimeter of water?
The unit ventilator and CPAP pressures are set in.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do Pa to cmH₂O in my head?
Plenty of people do this in their head: divide by 100 instead of using the exact factor 0.01019716213. At 100 that shortcut gives 1 centimeters of water, off by 0.01972 centimeters of water or about 1.93%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Pascals to centimeters of water reference tables
| Pascals | Centimeters Of Water |
|---|---|
| 0.5 Pa | 0.00509858 cmH₂O |
| 1 Pa | 0.0101972 cmH₂O |
| 2 Pa | 0.0203943 cmH₂O |
| 3 Pa | 0.0305915 cmH₂O |
| 5 Pa | 0.0509858 cmH₂O |
| 10 Pa | 0.101972 cmH₂O |
| 20 Pa | 0.203943 cmH₂O |
| 25 Pa | 0.254929 cmH₂O |
| 50 Pa | 0.509858 cmH₂O |
| 75 Pa | 0.764787 cmH₂O |
| 100 Pa | 1.01972 cmH₂O |
| 250 Pa | 2.54929 cmH₂O |
| 500 Pa | 5.09858 cmH₂O |
| 1000 Pa | 10.1972 cmH₂O |
| 5000 Pa | 50.9858 cmH₂O |
Exact factor: 1 pascal = 0.0101971621298 centimeters of water.
| Quantity | Pa | cmH₂O |
|---|---|---|
| Sea-level air | 1.013e+05 Pa | 1033 cmH₂O |
| A car tyre | 2.206e+05 Pa | 2250 cmH₂O |
| Blood pressure, systolic | 1.6e+04 Pa | 163.1 cmH₂O |
| A bicycle tyre | 6.205e+05 Pa | 6328 cmH₂O |
| A domestic water main | 4e+05 Pa | 4079 cmH₂O |
| A steam boiler | 1e+06 Pa | 1.02e+04 cmH₂O |
Published reference values, converted with the same factor this page uses.